🥜 goober, a less than 1KB css-in-js solution.

Can you shave off bytes from goober? Do it and your gonna get paid! More info here

I always wondered, if you can get a working solution for css-in-js with a smaller footprint. So, while I was working on a side-project I wanted a to use styled-components or more accurate the styled pattern. Looking at the JavaScript bundled sizes, I quickly realized that I would have to include ~12kB(styled-components) or ~11kB(emotion) just so I can use the styled paradigm. So, I embarked in a mission to create a smaller alternative for these well established apis.

It's a pun on the tagline.

css-in-js at the cost of peanuts! 🥜goober

• Usage
• Examples
• Tradeoffs
• SSR
• Benchmarks
  • Browser
  • SSR
• API
  • styled
  • setup
    • With prefixer
    • With theme
    • With forwardProps
  • css
  • targets
  • extractCss
  • createGlobalStyles
  • keyframes
  • shouldForwardProp
• Integrations
  • Babel Plugin
  • Babel Macro Plugin
  • Next.js
  • Gatsby
  • Preact CLI Plugin
  • CSS Prop
• Features
  • Sharing Style
  • Autoprefixer
  • TypeScript
• Browser Support
• Contributing

The API is inspired by emotion, styled function. Meaning, you call it with your tagName and returns a vDOM component for that tag. Note, setup is needed to be run before the styled function is used.

import { h } from 'preact';
import { styled, setup } from 'goober';

// Should be called here, and just once
setup(h);

const Icon = styled('span')`
    display: flex;
    flex: 1;
    color: red;
`;

const Button = styled('button')`
    background: dodgerblue;
    color: white;
    border: ${Math.random()}px solid white;

    &:focus,
    &:hover {
        padding: 1em;
    }

    .otherClass {
        margin: 0;
    }

    ${Icon} {
        color: black;
    }
`;

• Vanilla
• React
• Preact
• SSR with Preact
• Fre

In this section I would like to describe as objectively as I can the comparision between the two most known css-in-js packages: styled-component and emotion. The latest versions to date.

I would use the follwing markers to reflect the state of each point:

• ✅ Supported
• 🟡 Partially supported
• 🛑 Not supported

Here we go:

Footnotes

• [1] goober can render in any dom target. Meaning you can use goober to define scoped styles in any context. Really usefull for web-components.
• [2] Supported only via babel-plugin-transform-goober

You can get the critical CSS for SSR, via extractCss. Take a look at this example: CodeSandbox: SSR with Preact and goober and read the full explanation for extractCSS and targets below.

The results are included inside the build output as well.

Comming soon!

The benchmark is testing the following scenario:

import styled from 'package';

// Create the dynamic styled component
const Foo = styled('div')((props) => ({
    opacity: props.counter > 0.5 ? 1 : 0,
    '@media (min-width: 1px)': {
        rule: 'all'
    },
    '&:hover': {
        another: 1,
        display: 'space'
    }
}));

// Serialize the component
renderToString(<Foo counter={Math.random()} />);

The results are:

goober x 200,437 ops/sec ±1.93% (87 runs sampled)
styled-components@5.2.1 x 12,650 ops/sec ±9.09% (48 runs sampled)
emotion@11.0.0 x 104,229 ops/sec ±2.06% (88 runs sampled)

Fastest is: goober

As you can see it supports most of the syntaxes of CSS. If you find any issues, please submit a ticket or even a PR with a fix.

• @param {String|Function} tagName The name of the dom element you'd like the styled to be applied to
• @param {Function} forwardRef Forward ref function. Usually React.forwardRef
• @returns {Function} Returns the tag template function.

import { styled } from 'goober';

const Btn = styled('button')`
    border-radius: 4px;
`;

import { styled } from 'goober';

const Btn = styled('button')`
    border-radius: ${(props) => props.size}px;
`;

<Btn size={20} />;

import { styled } from 'goober';

const Btn = styled('button')(
    (props) => `
  border-radius: ${props.size}px;
`
);

<Btn size={20} />;

import { styled } from 'goober';

const Btn = styled('button')((props) => ({
    borderRadius: props.size + 'px'
}));

<Btn size={20} />;

import { styled } from 'goober';

const Btn = styled('button')([
    { color: 'tomato' },
    ({ isPrimary }) => ({ background: isPrimary ? 'cyan' : 'gray' })
]);

<Btn />; // This will render the `Button` with `background: gray;`
<Btn isPrimary />; // This will render the `Button` with `background: cyan;`

As goober is JSX library agnostic, you need to pass in the forward ref function for the library you are using. Here's how you do it for React.

const Title = styled('h1', React.forwardRef)`
    font-weight: bold;
    color: dodgerblue;
`;

The call to setup() should occur once only. It should be called in the entry file of you project.

Given the fact that react uses createElement for the transformed elements and preact uses h, setup should be called with the proper pragma function. This was added to reduce the bundled size and being able to bundle esmodule version. At the moment I think it's the best tradeoff we can have.

import React from 'react';
import { setup } from 'goober';

setup(React.createElement);

import React from 'react';
import { setup } from 'goober';

const customPrefixer = (key, value) => `${key}: ${value};\n`;

setup(React.createElement, customPrefixer);

import React, { createContext, useContext, createElement } from 'react';
import { setup, styled } from 'goober';

const theme = { primary: 'blue' };
const ThemeContext = createContext(theme);
const useTheme = () => useContext(ThemeContext);

setup(createElement, undefined, useTheme);

const ContainerWithTheme = styled('div')`
    color: ${(props) => props.theme.primary};
`;

The forwardProps function, offers a way to achieve the same shouldForwardProps functionality as emotion and styled-components(with transient props) offer. The difference in here is that the function receives the whole props and you are in charge of removing the props that are should not end-up in the dom.

This is a super useful functionality when paired with theme object, variants or any other customisation one might need.

import React from 'react';
import { setup, styled } from 'goober';

setup(React.createElement, undefined, undefined, (props) => {
    for (let prop in props) {
        // Or any other conditions.
        // This could also check if this is a dev build and not remove the props
        if (prop === 'size') {
            delete props[prop];
        }
    }
});

The functionality of "transient props" (with a "$" prefix) can be implemented as follows:

import React from 'react';
import { setup, styled } from 'goober';

setup(React.createElement, undefined, undefined, (props) => {
    for (let prop in props) {
        if (prop[0] === '$') {
            delete props[prop];
        }
    }
});

Alternatively you can use goober/should-forward-prop addon, to pass only the filter function and not have to deal with the full props object.

import React from 'react';
import { setup, styled } from 'goober';
import { shouldForwardProp } from 'goober/should-forward-prop';

setup(
    React.createElement,
    undefined,
    undefined,
    // This package accepts a `filter` function. If you return false that prop
    // won't be included in the forwarded props.
    shouldForwardProp((prop) => {
        return prop !== 'size';
    })
);

• @returns {String} Returns the className.

To create a className, you need to call css with your style rules in a tagged template.

import { css } from "goober";

const BtnClassName = css`
  border-radius: 4px;
`;

// vanilla JS
const btn = document.querySelector("#btn");
// BtnClassName === 'g016232'
btn.classList.add(BtnClassName);

// JSX
// BtnClassName === 'g016232'
const App => <button className={BtnClassName}>click</button>

import { css } from 'goober';

// JSX
const CustomButton = (props) => (
    <button
        className={css`
            border-radius: ${props.size}px;
        `}
    >
        click
    </button>
);

import { css } from 'goober';
const BtnClassName = (props) =>
    css({
        background: props.color,
        borderRadius: props.radius + 'px'
    });

Notice: using css with object can reduce your bundle size.

We also can declare the styles at the top of the file by wrapping css into a function that we call to get the className.

import { css } from 'goober';

const BtnClassName = (props) => css`
    border-radius: ${props.size}px;
`;

// vanilla JS
// BtnClassName({size:20}) -> g016360
const btn = document.querySelector('#btn');
btn.classList.add(BtnClassName({ size: 20 }));

// JSX
// BtnClassName({size:20}) -> g016360
const App = () => <button className={BtnClassName({ size: 20 })}>click</button>;

The difference between calling css directly and wrapping into a function is the timing of its execution. The former is when the component(file) is imported, the latter is when it is actually rendered.

If you use extractCSS for SSR, you may prefer to use the latter or styled api to avoid inconsistent results.

By default, goober will append a style tag to the <head> of a document. You might want to target a different node, for instance, when you want to use goober with web components (so you'd want it to append style tags to individual shadowRoots). For this purpose, you can .bind a new target to the styled and css methods:

import * as goober from 'goober';
const target = document.getElementById('target');
const css = goober.css.bind({ target: target });
const styled = goober.styled.bind({ target: target });

If you don't provide a target, goober always defaults to <head> and in environments without a DOM (think certain SSR solutions), it will just use a plain string cache to store generated styles which you can extract with extractCSS(see below).

• @returns {String}

Returns the <style> tag that is rendered in a target and clears the style sheet. Defaults to <head>.

const { extractCss } = require('goober');

// After your app has rendered, just call it:
const styleTag = `<style id="_goober">${extractCss()}</style>`;

// Note: To be able to `hydrate` the styles you should use the proper `id` so `goober` can pick it up and use it as the target from now on

To define your global styles you need to create a GlobalStyles component and use it as part of your tree. The createGlobalStyles is available at goober/global addon.

import { createGlobalStyles } from 'goober/global';

const GlobalStyles = createGlobalStyles`
  html,
  body {
    background: light;
  }

  * {
    box-sizing: border-box;
  }
`;

export default function App() {
    return (
        <div id="root">
            <GlobalStyles />
            <Navigation>
            <RestOfYourApp>
        </div>
    )
}

Before the global addon, goober/global, there was a method named glob that was part of the main package that would do the same thing, more or less. Having only that method to define global styles usually led to missing global styles from the extracted css, since the pattern did not enforced the evaluation of the styles at render time. The glob method it is still exported from goober/global if you have a hard dependency on it. It still has the same API:

import { glob } from 'goober';

glob`
  html,
  body {
    background: light;
  }

  * {
    box-sizing: border-box;
  }
`;

keyframes is a helpful method to define reusable animations that can be decoupled from the main style declaration and shared across components.

import { keyframes } from 'goober';

const rotate = keyframes`
    from, to {
        transform: rotate(0deg);
    }

    50% {
        transform: rotate(180deg);
    }
`;

const Wicked = styled('div')`
    background: tomato;
    color: white;
    animation: ${rotate} 1s ease-in-out;
`;

To seamingly implement the shouldForwardProp without the need to provide the full loop over props you can use the goober/should-forward-prop addon.

import { h } from 'preact';
import { setup } from 'goober';
import { shouldForwardProp } from 'goober/should-forward-prop';

setup(
    h,
    undefined,
    undefined,
    shouldForwardProp((prop) => {
        // Do NOT forward props that start with `$` symbol
        return prop['0'] !== '$';
    })
);

You're in love with the styled.div syntax? Fear no more! We got you covered with a babel plugin that will take your lovely syntax from styled.tag and translate it to goober's styled("tag") call.

npm i --save-dev babel-plugin-transform-goober
# or
yarn add --dev babel-plugin-transform-goober

Visit the package in here for more info (https://github.com/cristianbote/goober/tree/master/packages/babel-plugin-transform-goober)

A babel-plugin-macros macro for [🥜goober][goober], rewriting styled.div syntax to styled('div') calls.

Once you've configured babel-plugin-macros, change your imports from goober to goober/macro.

Now you can create your components using styled.* syntax:.

import { styled } from 'goober/macro';

const Button = styled.button`
    margin: 0;
    padding: 1rem;
    font-size: 1rem;
    background-color: tomato;
`;

Want to use goober with Next.js? We've got you covered! Follow the example below or from the main examples directory.

npx create-next-app --example with-goober with-goober-app
# or
yarn create next-app --example with-goober with-goober-app

Want to use goober with Gatsby? We've got you covered! We have our own plugin to deal with styling your Gatsby projects.

npm i --save goober gatsby-plugin-goober
# or
yarn add goober gatsby-plugin-goober

If you use Goober with Preact CLI, you can use preact-cli-goober-ssr

npm i --save-dev preact-cli-goober-ssr
# or
yarn add --dev preact-cli-goober-ssr

# preact.config.js
const gooberPlugin = require('preact-cli-goober-ssr')

export default (config, env) => {
  gooberPlugin(config, env)
}

When you build your Preact application this will run extractCss on your prerendered pages and add critical styles for each page.

You can use a custom css prop to pass in styles on HTML elements with this Babel plugin.

Installation:

npm install --save-dev @agney/babel-plugin-goober-css-prop

List the plugin in .babelrc:

{
  "plugins": [
    "@agney/babel-plugin-goober-css-prop"
  ]
}

Usage:

<main
    css={`
        display: flex;
        min-height: 100vh;
        justify-content: center;
        align-items: center;
    `}
>
    <h1 css="color: dodgerblue">Goober</h1>
</main>

• Basic CSS parsing
• Nested rules with pseudo selectors
• Nested styled components
• Extending Styles
• Media queries (@media)
• Keyframes (@keyframes)
• Smart(lazy) client-side hydration
• Styling any component
  • via const Btn = ({className}) => {...}; const TomatoBtn = styled(Btn)`color: tomato;`
• Vanilla(via css function)
• globalStyle(via glob) so one would be able to create global styles
• target/extract from elements other than <head>
• vendor prefixing

There are a couple of ways to effectly share/extend styles across components.

One can simply extend the desired component that needs to be enrich or overwriten with another set of css rules.

import { styled } from 'goober';

// Let's declare a primitive for our styled component
const Primitive = styled('span')`
    margin: 0;
    padding: 0;
`;

// Later on we could get the primitive shared styles and also add our owns
const Container = styled(Primitive)`
    padding: 1em;
`;

Another helpful way to extend a certain component is with the as property. Given our example above we could modify it like:

import { styled } from 'goober';

// Our primitive element
const Primitive = styled('span')`
    margin: 0;
    padding: 0;
`;

const Container = styled('div')`
    padding: 1em;
`;

// At composition/render time
<Primitive as={'div'} /> // <div class="go01234" />

// Or using the `Container`
<Primitive as={Container} /> // <div class="go01234 go56789" />

Autoprefixing is a helpful way to make sure the generated css will work seamlessly on the whole spectrum of browsers. With that in mind, the core goober package can't hold that logic to determine the autoprefixing needs, so we added a new package that you can choose to address them.

npm install goober
# or
yarn add goober

After the main package is installed it's time to bootstrap goober with it:

import { setup } from 'goober';
import { prefix } from 'goober/prefixer';

// Bootstrap goober
setup(React.createElement, prefix);

And voila! It is done!

goober comes with type definitions build in, making it easy to get started in TypeScript straight away.

If you're utilising custom props and wish to style based on them, you can do so when initialising as follows:

interface Props {
    size: number;
}

styled('div')<Props>`
    border-radius: ${(props) => props.size}px;
`;

// This also works!

styled<Props>('div')`
    border-radius: ${(props) => props.size}px;
`;

If you're using a custom theme with goober, to add types to it you should create a declaration file at the base of your project.

// goober.d.t.s

import 'goober';

declare module 'goober' {
    export interface DefaultTheme {
        colors: {
            primary: string;
        };
    }
}

You should now have autocompletion for your theme.

const ThemeContainer = styled('div')`
    background-color: ${(props) => props.theme.colors.primary};
`;

goober uses microbundle to bundle and transpile it's src into code that browsers can leverage. As you might figure it out, until now, Internet Explorer was the buggiest of them all. goober works on IE9, as we've successfully test it.

IE 9
iOS 9.3
Chrome 42
FF 34
Safari 9

Feel free to try it out and checkout the examples. If you wanna fix something feel free to open a issue or a PR.

Thank you to all our backers! 🙏

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